Selecting and assinging ProTrackR2 objects

Samples

Selecting a specific sample from a sample list can be done with the [[-operator. Note that sample number 5 is empty (consists of zero samples):

mod$samples[[5L]]
#> [1] "PT2 Sample 'commodore amiga 500' [0]"
## which is identical to (see the different base of the index)
pt2_sample(mod, 4L)
#> [1] "PT2 Sample 'commodore amiga 500' [0]"

In order to replace this sample with sample number 2, you can simply assign it like this:

mod$samples[[5L]] <- mod$samples[[2L]]

After this assignment operation samples 2 and 5 are identical. If you want to replace multiple samples at once you need to use the [-operator. The example below shows how to replace samples 5 up to 8 with sample 2:

mod$samples[5L:8L] <- mod$samples[2L]

Single brackets [ returns a list (pt2samplist) with one or more elements. Double brackets [[ return a single element (pt2samp). In essence, this works the same as with normal list objects.

Patterns

For a pattern lists (pt2patlist) selection and assignment operators are similar to those of sample lists (see above). Single brackets [ returns a list (pt2patlist) with one or more elements. Double brackets [[ return a single element (pt2pat). In essence, this works the same as with normal list objects.

The range of pattern indices you can use depends on the maximum index (+1) registered in the pattern sequence table (pt2_pattern_table(mod)). In the currently loaded module there are 4 patterns registered. So to get the fourth pattern table in the module, you use:

my_pattern <- mod$patterns[[4L]]
## which is identical to (see the different base of the index)
my_pattern <- pt2_pattern(mod, 3L)

If you attempt to get the fifth table (mod$patterns[[5]]), you will get an error, since it doesn’t exist. However, you can append a new pattern table at this position using the assign operator:

mod$patterns[[5L]] <- pt2_new_pattern()

This new pattern is also automatically added to the pattern sequence table:

pt2_pattern_table(mod)
#>   [1] 0 0 1 1 2 2 3 3 2 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
#>  [38] 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
#>  [75] 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
#> [112] 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

You can use the same strategy to copy existing patterns to a new index:

mod$patterns[[6L]] <- mod$patterns[[1L]]

In theory ProTracker modules can hold a maximum of 100 pattern tables. If this limit can be reached depends on available slots in the pattern sequence table (pt2_pattern_table(mod)). If you try to create a pattern beyond the maximum of 100 or there are no more room for additional patterns in the sequence table, you will get an error.

Cells

As explained in vignette("s3class"), a cell (class pt2cell) is the elementary unit of a pattern table and specifies which instrument (sample) to play at which note and with which effect. You can select a range of cells with a [-operator by referring to a pattern’s row index and its channel (column) index. The example below selects the first 8 rows from the first channel.

my_cells <- mod$patterns[[1L]][1L:8L, 1L]

The result of this is an object of class pt2celllist. To select a particular cell from this range you need the double bracket operator [[. To select the first cell of the eight selected cells you do the following.

my_cells[[1L]]
#> C-3 01 A08
## which is identical to (see the different base of the indices)
pt2_cell(pt2_pattern(mod, 0L), i = 0L, j = 0L)
#> C-3 01 A08

Remember that we appended an empty pattern at position 5? We can replace the empty cells in that pattern with the selected cells. The example below shows how the entire first column is filled with the 8 selected cells (note that the cells are recycled).

mod$patterns[[5L]][,1L] <- my_cells
#> Warning in replace_cells_(x, as.matrix(target_idx), values): Replacement values
#> are recycled